The invention relates to a method of measuring dimensional rough stone blocks, in which method the outer dimensions of a dimensional rough stone block are measured and the amount of useful material in the block is determined on the basis of the conducted measurements.
The invention further relates to an apparatus for measuring a dimensional rough stone block.
Dimensional rough stone blocks are quarried from rock in order to process the blocks into rock material that is suitable for different purposes. At present, such rock material is used increasingly for different surface or coating materials for which purpose the rock is sawn into rather thin sheets. When a large block of a suitable size has been cut off, it is sawed into smaller pieces as required in each case. In order for the sawing of a rough stone block to be as cost-effective as possible, the shape of the block must be measured, whereafter a plan is devised for the use of the block based on the measurement result. Another purpose of the measurement is that when the haulage of the blocks from the quarry to the place where they are to be processed is being planned, the weight of the blocks must also be known.
A rough stone block is measured in three main directions where gross length, gross height and gross width are determined. These are used to calculate the gross volume of the block and its weight on the basis of the density properties of the rock material in question. When the weight is calculated, it is naturally also necessary to take into account possible deviations of the block from a basic rectangular shape. Useful rock volume of a rough stone block is obtained, in principle, by in a way placing an imaginary rectangular prism about the block to establish maximum outer dimensions of the block, and by subtracting a working allowance of 5 to 10 cm from the obtained principal dimensions. The results of the measurement are stored specifically for each rough block, so that the basic data for the sale and processing of the block already exist.
The aforementioned measurements carried out conventionally by means of a measuring tape and visual evaluation of the dimensions are useful as such, but in the worst case they take a lot of time especially when the shape of the block differs substantially from rectangular. Also, determining the useful rock volume in this manner causes errors which become apparent in the lower degree of usability of the block than presumed and in too great haulage weights, among other things.
The purpose of the present invention is to provide a method and an apparatus which provide as efficient and reliable measurement of a dimensional rough stone block as possible, and more reliable and accurate measurement and evaluation of the block than previously.
The method according to the invention is characterized by the measurement of the stone block being carried out in a three-dimensional coordinate system by means of an inertia measuring device such that the device is placed at suitable measuring points on the surface of the block, and the dimensions and shape of the block being calculated on the basis of the values of the measuring points determined by the inertia measuring device in the three-dimensional coordinate system.
The apparatus according to the invention is characterized in that it comprises an inertia measuring device which measures the location of a certain point on the surface of the rough stone block to be measured in the three-dimensional coordinate system, and a calculating device to which the values of the points of the block measured with the inertia measuring device in said three-dimensional coordinate system can be transferred and with which the dimensions and shape of the measured block in the three-dimensional coordinate system can be calculated on the basis of said measured points.
The basic idea of the invention is that the dimensions of a block are measured by utilizing inertia location, wherein an inertia measuring device is first placed in one suitable measuring point and then moved therefrom to several other measuring points in a suitable order and finally placed most preferably again in the first measuring point to take into account errors that have possibly occurred during the measurement. An inertia measuring device, which at the moment of measurement is in contact with the rough stone block to be measured, enables measurement of the location of the measuring points in the surrounding three-dimensional coordinate system and storing of the results in a memory of a calculating device, such as a computer, which is thereafter able to calculate, on the basis of the measured points of the surface, the shape of the block and, for example, the useful amount and weight of the rock material obtained from the block.